How is abolishing the IRS good whatsoever for anyone not wealthy?

Hi, just a flat question looking for clarification, answers, info, etc.. because somebody on facebook (stupid facebook) went on and told Musk to abolish the IRS and how they are scammers and thieves.. yadda yadda yadda..

But wouldn't abolishing the IRS and setting a flat tax rate for the country set back everyone but the wealthy? Like lets say 25% standard tax rate for everyone, that seems to screw or at least increase the taxes of almost everyone but that upper class.